Combined detection of depression and anxiety in epilepsy patients using the Neurological Disorders Depression Inventory for Epilepsy and the World Health Organization well-being index

PURPOSE: To validate the Danish version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), and compare it with the World Health Organization index for psychological well-being (WHO-5) as screening tests for depression and anxiety in epilepsy patients.

METHODS: Epilepsy outpatients filled out NDDI-E and WHO-5. A Mini International Neuropsychiatric Interview (MINI) as gold standard for psychiatric diagnoses was carried out with every patient.

RESULTS: We included 124 epilepsy patients. According to MINI, 5% had depression without anxiety, 6% anxiety without depression, and 6% had both. For the detection of depression, NDDI-E was slightly better than WHO-5. With a score of more than 13, NDDI-E as a screening tool for depression had a sensitivity of 0.92, a specificity of 0.84, a positive predictive value (PPV) of 0.40, and a negative predictive value (NPV) of 0.99. In the detection of anxiety WHO-5 was better than NDDI-E. With a score below 50, WHO-5 as screening for anxiety had a sensitivity of 0.80, a specificity of 0.92, PPV 0.57, and NPV 0.97. When combining NDDI-E>13 and WHO-5<50, 95% of patients with depression and/or anxiety are identified, and in addition there are 17% false positives.

CONCLUSION: NDDI-E in Danish is valid and slightly better than WHO-5 in the detection of depression in epilepsy patients. WHO-5 is valid for the detection of anxiety disorders. Combined use of NDDI-E and WHO-5 is recommended, since 95% of all epilepsy patients with depression and/or anxiety disorder are identified with only a modest number of false positives.